A known corpuscle-detecting apparatus passes a liquid sample containing blood cells or other corpuscles through an aperture in a detector portion and detects individual corpuscles, based on the difference in electrical impedance between the liquid and each corpuscle.
FIG. 12 is a block diagram of such a corpuscle-detecting apparatus. This apparatus comprises a detector portion 102 having an aperture 101. A power supply 100 supplies a constant current to the aperture 101. Individual corpuscles are detected by the detector portion 102. The output signal 103 from this detector portion 102 is sent to an amplifier circuit 104, a waveform-processing circuit 106, an A/D converter circuit 108, and a data-processing circuit 110 which are disposed behind the detector portion 102. The signal is processed in these circuits in given manner, and the number and the sizes of the corpuscles are detected.
The corpuscle-detecting apparatus is required to adjust the sensitivity thereof and to check or monitor the operation of the circuits. Such adjustment and checking or monitoring has been done by the prior art techniques in the manner described below.